#!/usr/bin/env python2
# -*- coding: utf-8 -*-
#
# Copyright (C) 2009-2014:
#    Gabes Jean, naparuba@gmail.com
#    Gerhard Lausser, Gerhard.Lausser@consol.de
#    Gregory Starck, g.starck@gmail.com
#    Hartmut Goebel, h.goebel@goebel-consult.de
#
# This file is part of Shinken.
#
# Shinken is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Shinken is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with Shinken.  If not, see <http://www.gnu.org/licenses/>.

"""The AutoSlots Class is a MetaClass: it manages how other classes
 are created (Classes, not instances of theses classes).
 Here it's role is to create the __slots__ list of the class with
 all properties of Class.properties and Class.running_properties
 so we do not have to add manually all properties to the __slots__
 list when we add a new entry"""


class AutoSlots(type):

    # new is call when we create a new Class
    # that have metaclass = AutoSlots
    # CLS is AutoSlots
    # name is string of the Class (like Service)
    # bases are the Classes of which Class inherits (like SchedulingItem)
    # dct is the new Class dict (like all method of Service)
    # Some properties names are not allowed in __slots__ like 2d_coords of
    # Host, so we must tag them in properties with no_slots
    def __new__(cls, name, bases, dct):
        # Thanks to Bertrand Mathieu to the set idea
        slots = dct.get('__slots__', set())
        # Now get properties from properties and running_properties
        if 'properties' in dct:
            props = dct['properties']
            slots.update((p for p in props
                          if not props[p].no_slots))
        if 'running_properties' in dct:
            props = dct['running_properties']
            slots.update((p for p in props
                          if not props[p].no_slots))
        dct['__slots__'] = tuple(slots)
        return type.__new__(cls, name, bases, dct)
